When running low on memory, programs are swapped from memory to disk which can make them slow and unresponsive.

It may help to reduce the number of content processes per site by going to about:config and changing dom.ipc.processCount.webIsolated to 1 then restarting the browser.

I don't think that memory is the problem. This is Win 7 Pro with 16Gb of memory. I don't have similar uissues with any other programs hanging. What is the best way to catch this? Task Manager? What do I specifically look for?

Thanks, Steve

You can find the current multi-process state on the Troubleshooting Information page (about:support).

• "Help -> Troubleshooting Information"
  "Application Basics":<be>Multiprocess Windows and Fission Windows
  "Remote Processes" (Web Content)

You can check the about:memory and about:processes pages for info about all processes. There are several toolkit.aboutProcesses prefs on the about:config page to show more info. See also the about:unloads page for info about the tabs.

• https://Firefox-source-docs.mozilla.org/browser/tabunloader/

See also:

• https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-or-cpu-resources
• https://support.mozilla.org/en-US/kb/quick-fixes-if-your-firefox-slows-down

Try disabling the disk cache by going to about:config and changing browser.cache.disk.enable to false then restarting the browser. This avoids the virus scanner having to constantly scan cache files written to disk.

I don't think that memory is the problem. This is Win 7 Pro with 16Gb of memory. I don't have similar uissues with any other programs hanging. What is the best way to catch this? Task Manager? What do I specifically look for? Thanks, Steve

Well, here is some more information... I actually started Task Manager with the Performance tab open where it shows CPU and memory usage. All of my previously open windows and tabs loaded and then minimized. TM was showing about 9.8 Gb used. I then maximized a minimized window which created a hang of about 30-45 seconds banging on the disk full time. During this time TM memory usage went up to maybe 10 Gb so clearly FF wasn't running out of memory.

Any other suggestions n how to track this down? Any log files created that might have some interesting information? I hate to start making random configuration changes on an issue that is non-reproducible and crossing my fingers.

Thanks, Steve

Try disabling the disk cache by going to about:config and changing browser.cache.disk.enable to false then restarting the browser. This avoids the virus scanner having to constantly scan cache files written to disk.

What virus scanner are you referring to? Is there one built into FF?

Thanks, Steve

Any virus scanner you may have, whether third-party of the default Window Defender. Firefox has Google Safe Browsing for checking malicious sites and downloads but this does not apply to the cache.

Are you using the 32bit or 64bit version of Firefox? You can find this at the end of the version number in ≡ > Help > About Firefox.

Does it still happen in Troubleshoot Mode?

Are you using the 32bit or 64bit version of Firefox? You can find this at the end of the version number in ≡ > Help > About Firefox.

64-bit

Does it still happen in Troubleshoot Mode?

Haven't tried troubleshoot mode. If I do will I loose all of my open windows and tabs? Help page doesn't mention this and I don't want to find out the hard way.

Thanks, Steve

The tab session is retained in Troubleshoot Mode. You could alternatively try disabling all your extensions.

The tab session is retained in Troubleshoot Mode. You could alternatively try disabling all your extensions.

The only extension that I have is AdBlock Plus. Is it still worth trying troubleshoot mode?

Thanks, Steve

Troubleshoot Mode does more than just disable extensions.

You could try substituting AdBlock Plus with uBlock Origin and see if it still happens.

Well, The issue seems to have resolved itself. I suspect that FF choked on some web page that was open in one of my windows. I seem to recall similar issues a couple of years ago. So what web page issues could make FF behave like this?

Thanks, Steve